RQC Seminar

172nd RQC Seminar

• Speaker

  Dr. Patrice Bertet
  ( Quantronics Group SPEC/CEA Saclay )

• Date

  14:00-15:00 (2:00 -3:00 p.m.), December 6, 2024 (Friday)

• Venue

  Hybrid(ZOOM・ Large Meeting Room at Wako Welfare ＆ Conf. 2F (C61))

• Title

  Month-long-lifetime microwave spectral holes in an erbium-doped scheelite crystal at millikelvin temperature

• Inquiries

  yasunobu.nakamura[at]riken.jp

Abstract
Rare-earth-ion (REI) ensembles in crystals have remarkable optical and spin properties characterized by narrow homogeneous linewidths relative to the inhomogeneous ensemble broadening. This makes it possible to precisely tailor the ensemble spectral density and therefore the absorption profile by applying narrow-linewidth radiation to transfer population into auxiliary levels, a process broadly known as spectral hole burning (SHB). REI-doped crystals find applications in information processing, both classical (pattern recognition, filtering, spectral analysis) and quantum (photon storage), all protocols requiring suitable ensemble preparation by SHB as a first step. In Er3+-doped materials, the longest reported hole lifetime is one minute, and longer lifetimes are desirable. Here, we report SHB and accumulated echo measurements in a scheelite crystal of CaWO4 by pumping the electron spin transition of Er3+ ions at microwave frequencies and millikelvin temperatures, with nuclear spin states of neighboring 183W atoms serving as the auxiliary levels. The lifetime of the holes and accumulated echoes rises steeply as the sample temperature is decreased, exceeding a month at 10 mK. Our results demonstrate that millikelvin temperatures can be beneficial for signal processing applications requiring long spectral hole lifetimes.